// Set 在红黑树中体现为 key = value
// 不允许通过set迭代器改变set元素值
#include <functional>
#include "../allocator/alloc.h"


template<typename Key,
         typename Compare = std::less<Key>,
         typename Alloc = alloc>
class set
{
    using key_type = Key;
    using value_type = Key;
    using key_compare = Compare;
    using value_compare = Compare;
    
}